Photocatalytic degradation of Rhodamine B by C3N4 with continuous defective areas
A C3N4 photocatalyst with a continuous distribution of defect areas(C3N4-C)was prepared using high-temperature(600℃)thermal polymerization.Multiple technical methods were employed for its characterization,and C3N4-C was used for the photocatalytic degradation of Rhodamine B(RhB).The catalytic degradation effect and mechanism of C3N4-C on RhB were investigated.Characterization results show that in traditional C3N4(C3N4-I),the defect areas,densely distributed but small in size,exist in isolation and not interconnected;while in C3N4-C,the defect areas are larger and interconnected,almost forming a flaky distribution.Compared to C3N4-I,the continuous defect areas in C3N4-C delay the trapping and recombination of photogenerated charge carriers,extending their lifetime,optimizing the charge carrier dynamics,and enhancing the photocatalytic activity of C3N4-C.Under conditions of a RhB mass concentration of 10 mg/L and a catalyst dosage of 0.5 g/L,after 90 min of irradiation,the RhB removal rates in the C3N4-C and C3N4-I systems are 97.5%and 86.2%,respectively;after 120 min of irradiation,the RhB removal rate in the C3N4-C system is close to 100%.The corresponding pseudo-first-order kinetic rate constants of catalytic degradation of C3N4-C and C3N4-I on RhB are 0.040 78 min-1 and 0.026 94 min-1.After 4 cycles of use,the RhB removal rate of C3N4-C is greater than 99%,demonstrating good regenerability.The main active species in the photocatalytic degradation of RhB by C3N4-C are·OH,h+,and·O2-.
continuous defective areasC3N4carrier dynamicsphotocatalytic degradationRhodamine B
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